Maybe you help me too.
In 90's I had some old pc, including intel dx 286, 386, 486, and I believe the game I search was for one of these pc. Pretty sure, OS was DOS.
The game was about futuristic tank (I guess that was a tank, but I'm not sure. The picture how I remember this tank is here http://i.imgur.com/jbuKdlR.png - yes, it haven't any wheels or tracks as I remember, and it has windowed cabin) going through level, destroying turrets and other tanks. Levels was atmost flat (2 heights: height1 is ground and height2 is some hills, also flat) and limited by mountains or walls. Color scheme was dark, sky was black, as I remember.
Tank projectiles illuminated light on earth under it.
It had first person view, controls was forward/backward and left/right, no strafe.
Level 1 was looking like that http://i.imgur.com/BqX1529.png
Games that look sililar:
stellar 7 - close, but no.
battlezone 1 - very close, but that game had textures(not sure) or filled with color polygons.